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CHEMICAL ENGINEERING (190 journals)                     

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AATCC Journal of Research     Full-text available via subscription   (Followers: 6)
ACS Sustainable Chemistry & Engineering     Hybrid Journal   (Followers: 3)
Acta Crystallographica Section B: Structural Science, Crystal Engineering and Materials     Hybrid Journal   (Followers: 5)
Acta Polymerica     Hybrid Journal   (Followers: 9)
Additives for Polymers     Full-text available via subscription   (Followers: 20)
Adhesion Adhesives & Sealants     Hybrid Journal   (Followers: 7)
Advanced Chemical Engineering Research     Open Access   (Followers: 30)
Advanced Powder Technology     Hybrid Journal   (Followers: 16)
Advances in Applied Ceramics     Hybrid Journal   (Followers: 5)
Advances in Chemical Engineering     Full-text available via subscription   (Followers: 24)
Advances in Chemical Engineering and Science     Open Access   (Followers: 53)
Advances in Polymer Technology     Hybrid Journal   (Followers: 13)
African Journal of Pure and Applied Chemistry     Open Access   (Followers: 7)
Annual Review of Analytical Chemistry     Full-text available via subscription   (Followers: 9)
Annual Review of Chemical and Biomolecular Engineering     Full-text available via subscription   (Followers: 12)
Anti-Corrosion Methods and Materials     Hybrid Journal   (Followers: 7)
Applied Petrochemical Research     Open Access   (Followers: 2)
Asia-Pacific Journal of Chemical Engineering     Hybrid Journal   (Followers: 7)
Biochemical Engineering Journal     Hybrid Journal   (Followers: 15)
Biofuel Research Journal     Open Access   (Followers: 4)
Biomass Conversion and Biorefinery     Partially Free   (Followers: 10)
Brazilian Journal of Chemical Engineering     Open Access   (Followers: 3)
Bulletin of Chemical Reaction Engineering & Catalysis     Open Access   (Followers: 2)
Bulletin of the Chemical Society of Ethiopia     Open Access   (Followers: 3)
Carbohydrate Polymers     Hybrid Journal   (Followers: 8)
Catalysts     Open Access   (Followers: 7)
ChemBioEng Reviews     Full-text available via subscription   (Followers: 1)
Chemical and Engineering News     Free   (Followers: 12)
Chemical and Materials Engineering     Open Access   (Followers: 12)
Chemical and Petroleum Engineering     Hybrid Journal   (Followers: 12)
Chemical and Process Engineering     Open Access   (Followers: 25)
Chemical and Process Engineering Research     Open Access   (Followers: 22)
Chemical Engineering & Technology     Hybrid Journal   (Followers: 32)
Chemical Engineering and Processing: Process Intensification     Hybrid Journal   (Followers: 18)
Chemical Engineering and Science     Open Access   (Followers: 17)
Chemical Engineering Communications     Hybrid Journal   (Followers: 13)
Chemical Engineering Education     Full-text available via subscription  
Chemical Engineering Journal     Hybrid Journal   (Followers: 32)
Chemical Engineering Research and Design     Hybrid Journal   (Followers: 21)
Chemical Engineering Research Bulletin     Open Access   (Followers: 11)
Chemical Engineering Science     Hybrid Journal   (Followers: 22)
Chemical Geology     Hybrid Journal   (Followers: 18)
Chemical Papers     Hybrid Journal   (Followers: 2)
Chemical Product and Process Modeling     Hybrid Journal   (Followers: 3)
Chemical Reviews     Full-text available via subscription   (Followers: 163)
Chemical Society Reviews     Full-text available via subscription   (Followers: 41)
Chemical Technology     Open Access   (Followers: 15)
ChemInform     Hybrid Journal   (Followers: 7)
Chemistry & Industry     Hybrid Journal   (Followers: 4)
Chemistry Central Journal     Open Access   (Followers: 4)
Chemistry of Materials     Full-text available via subscription   (Followers: 176)
Chemometrics and Intelligent Laboratory Systems     Hybrid Journal   (Followers: 15)
ChemSusChem     Hybrid Journal   (Followers: 7)
Chinese Chemical Letters     Full-text available via subscription   (Followers: 3)
Chinese Journal of Chemical Engineering     Full-text available via subscription   (Followers: 4)
Chinese Journal of Chemical Physics     Hybrid Journal   (Followers: 1)
Coke and Chemistry     Hybrid Journal   (Followers: 1)
Coloration Technology     Hybrid Journal  
Computational Biology and Chemistry     Hybrid Journal   (Followers: 11)
Computer Aided Chemical Engineering     Full-text available via subscription   (Followers: 1)
Computers & Chemical Engineering     Hybrid Journal   (Followers: 10)
CORROSION     Full-text available via subscription   (Followers: 20)
Corrosion Engineering, Science and Technology     Hybrid Journal   (Followers: 36)
Corrosion Reviews     Hybrid Journal   (Followers: 4)
Crystal Research and Technology     Hybrid Journal   (Followers: 6)
Current Opinion in Chemical Engineering     Open Access   (Followers: 8)
Education for Chemical Engineers     Hybrid Journal   (Followers: 5)
Eksergi     Open Access  
Emerging Trends in Chemical Engineering     Full-text available via subscription   (Followers: 2)
European Polymer Journal     Hybrid Journal   (Followers: 41)
Fibers and Polymers     Full-text available via subscription   (Followers: 6)
Fluorescent Materials     Open Access   (Followers: 1)
Focusing on Modern Food Industry     Open Access   (Followers: 2)
Frontiers of Chemical Science and Engineering     Hybrid Journal   (Followers: 2)
Gels     Open Access  
Geochemistry International     Hybrid Journal   (Followers: 2)
Handbook of Powder Technology     Full-text available via subscription   (Followers: 6)
Heat Exchangers     Open Access   (Followers: 3)
High Performance Polymers     Hybrid Journal   (Followers: 1)
Hungarian Journal of Industry and Chemistry     Open Access  
Indian Chemical Engineer     Hybrid Journal   (Followers: 5)
Indian Journal of Chemical Technology (IJCT)     Open Access   (Followers: 10)
Indonesian Journal of Chemical Science     Open Access   (Followers: 1)
Industrial & Engineering Chemistry     Full-text available via subscription   (Followers: 11)
Industrial & Engineering Chemistry Research     Full-text available via subscription   (Followers: 21)
Industrial Chemistry Library     Full-text available via subscription   (Followers: 3)
Industrial Gases     Open Access  
Info Chimie Magazine     Full-text available via subscription   (Followers: 3)
International Journal of Chemical and Petroleum Sciences     Open Access   (Followers: 2)
International Journal of Chemical Engineering     Open Access   (Followers: 7)
International Journal of Chemical Reactor Engineering     Hybrid Journal   (Followers: 3)
International Journal of Chemical Technology     Open Access   (Followers: 5)
International Journal of Chemoinformatics and Chemical Engineering     Full-text available via subscription   (Followers: 2)
International Journal of Food Science     Open Access   (Followers: 3)
International Journal of Industrial Chemistry     Open Access   (Followers: 1)
International Journal of Polymeric Materials     Hybrid Journal   (Followers: 5)
International Journal of Science and Engineering     Open Access   (Followers: 4)
International Journal of Waste Resources     Open Access   (Followers: 4)
Journal of Chemical Engineering & Process Technology     Open Access   (Followers: 4)
Journal of Applied Crystallography     Hybrid Journal   (Followers: 6)
Journal of Applied Electrochemistry     Hybrid Journal   (Followers: 12)
Journal of Applied Polymer Science     Hybrid Journal   (Followers: 116)
Journal of Biomaterials Science, Polymer Edition     Hybrid Journal   (Followers: 9)
Journal of Bioprocess Engineering and Biorefinery     Full-text available via subscription   (Followers: 1)
Journal of Chemical & Engineering Data     Full-text available via subscription   (Followers: 11)
Journal of Chemical and Biological Interfaces     Full-text available via subscription   (Followers: 1)
Journal of Chemical Ecology     Hybrid Journal   (Followers: 7)
Journal of Chemical Engineering     Open Access   (Followers: 18)
Journal of Chemical Engineering and Materials Science     Open Access   (Followers: 2)
Journal of Chemical Science and Technology     Open Access   (Followers: 4)
Journal of Chemical Sciences     Partially Free   (Followers: 17)
Journal of Chemical Technology & Biotechnology     Hybrid Journal   (Followers: 10)
Journal of Chemical Theory and Computation     Full-text available via subscription   (Followers: 15)
Journal of CO2 Utilization     Hybrid Journal   (Followers: 2)
Journal of Combinatorial Chemistry     Full-text available via subscription  
Journal of Crystallization Process and Technology     Open Access   (Followers: 8)
Journal of Environmental Chemical Engineering     Hybrid Journal   (Followers: 4)
Journal of Food Measurement and Characterization     Hybrid Journal  
Journal of Food Processing & Technology     Open Access   (Followers: 1)
Journal of Fuel Chemistry and Technology     Full-text available via subscription   (Followers: 4)
Journal of Geochemical Exploration     Hybrid Journal   (Followers: 1)
Journal of Industrial and Engineering Chemistry     Hybrid Journal   (Followers: 1)
Journal of Information Display     Hybrid Journal   (Followers: 1)
Journal of Inorganic and Organometallic Polymers and Materials     Partially Free   (Followers: 9)
Journal of Modern Chemistry & Chemical Technology     Full-text available via subscription   (Followers: 2)
Journal of Molecular Catalysis A: Chemical     Hybrid Journal   (Followers: 5)
Journal of Non-Crystalline Solids     Hybrid Journal   (Followers: 8)
Journal of Organic Semiconductors     Open Access   (Followers: 5)
Journal of Physics and Chemistry of Solids     Hybrid Journal   (Followers: 5)
Journal of Polymer and Biopolymer Physics Chemistry     Open Access   (Followers: 4)
Journal of Polymer Engineering     Hybrid Journal   (Followers: 9)
Journal of Polymer Research     Hybrid Journal   (Followers: 6)
Journal of Polymer Science Part C : Polymer Letters     Hybrid Journal   (Followers: 6)
Journal of Polymers     Open Access   (Followers: 3)
Journal of Polymers and the Environment     Hybrid Journal   (Followers: 1)
Journal of Pure and Applied Chemistry Research     Open Access   (Followers: 1)
Journal of the American Chemical Society     Full-text available via subscription   (Followers: 283)
Journal of the Bangladesh Chemical Society     Open Access  
Journal of the Brazilian Chemical Society     Open Access   (Followers: 2)
Journal of The Institution of Engineers (India) : Series E     Hybrid Journal   (Followers: 1)
Journal of the Pakistan Institute of Chemical Engineers     Open Access   (Followers: 1)
Journal of the Taiwan Institute of Chemical Engineers     Hybrid Journal   (Followers: 2)
Journal of Water Chemistry and Technology     Hybrid Journal   (Followers: 9)
Jurnal Bahan Alam Terbarukan     Open Access  
Jurnal Inovasi Pendidikan Kimia     Open Access   (Followers: 4)
Jurnal Reaktor     Open Access  
Jurnal Teknologi Dan Industri Pangan     Open Access   (Followers: 1)
Konversi     Open Access  
Korean Journal of Chemical Engineering     Hybrid Journal   (Followers: 3)
Main Group Metal Chemistry     Hybrid Journal   (Followers: 1)
Materials Chemistry and Physics     Full-text available via subscription   (Followers: 15)
Materials Science and Applied Chemistry     Open Access  
Materials Sciences and Applied Chemistry     Full-text available via subscription  
Modern Chemistry & Applications     Open Access  
Molecular Imprinting     Open Access  
Nanocontainers     Open Access  
Nanofabrication     Open Access  
Noise Control Engineering Journal     Full-text available via subscription   (Followers: 3)
Ochrona Srodowiska i Zasobów Naturalnych : Environmental Protection and Natural Resources     Open Access  
Petroleum Chemistry     Hybrid Journal   (Followers: 1)
Physics and Chemistry of Glasses - European Journal of Glass Science and Technology Part B     Full-text available via subscription   (Followers: 4)
Plasma Processes and Polymers     Hybrid Journal   (Followers: 1)
Plasmas and Polymers     Hybrid Journal  
Polymer     Hybrid Journal   (Followers: 115)
Polymer Bulletin     Hybrid Journal   (Followers: 7)
Polymer Composites     Hybrid Journal   (Followers: 15)
Polyolefins Journal     Open Access  
Powder Technology     Hybrid Journal   (Followers: 14)
Recyclable Catalysis     Open Access   (Followers: 1)
Research on Chemical Intermediates     Hybrid Journal  
Reviews in Chemical Engineering     Hybrid Journal   (Followers: 5)
Revista ION     Open Access  
Revista Mexicana de Ingeniería Química     Open Access  
Rubber Chemistry and Technology     Full-text available via subscription   (Followers: 2)
Russian Chemical Bulletin     Hybrid Journal   (Followers: 2)
Russian Journal of Applied Chemistry     Hybrid Journal   (Followers: 1)
Science and Engineering of Composite Materials     Hybrid Journal   (Followers: 60)
Solid Fuel Chemistry     Hybrid Journal  
South African Journal of Chemical Engineering     Open Access   (Followers: 2)
South African Journal of Chemistry     Open Access   (Followers: 2)
Surface Engineering and Applied Electrochemistry     Hybrid Journal   (Followers: 5)
Sustainable Chemical Processes     Open Access   (Followers: 2)
Synthesis Lectures on Chemical Engineering and Biochemical Engineering     Full-text available via subscription  
The Canadian Journal of Chemical Engineering     Hybrid Journal   (Followers: 3)
The Chemical Record     Hybrid Journal   (Followers: 1)
Theoretical Foundations of Chemical Engineering     Hybrid Journal   (Followers: 2)
Transition Metal Chemistry     Hybrid Journal   (Followers: 3)
Transylvanian Review of Systematical and Ecological Research     Open Access  
Visegrad Journal on Bioeconomy and Sustainable Development     Open Access   (Followers: 2)
Zeitschrift für Naturforschung B : A Journal of Chemical Sciences     Open Access   (Followers: 1)


Journal Cover Chemical Engineering Science
  [SJR: 1.073]   [H-I: 135]   [22 followers]  Follow
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0009-2509
   Published by Elsevier Homepage  [3043 journals]
  • Printing particles: A high-throughput technique for the production of
           uniform, bioresorbable polymer microparticles and encapsulation of
           therapeutic peptides
    • Abstract: Publication date: 20 July 2017
      Source:Chemical Engineering Science, Volume 166
      Author(s): Daniel Palmer, Katie Bamsey, Rhian Groves, Prasad Patil, Huw Jones, Liam McAleer, Paul Seaman
      Bioresorbable polymer microparticles are widely used to provide long-lasting drug delivery in several chronic diseases. Having fine control over the physical properties of such microparticles can improve product reproducibility, performance and process efficiency. By using an ink-jet based droplet generator device, a new approach to microparticle manufacture was explored that uses an extremely rapid phase-separation to produce highly uniform, injectable microparticles from PLGA and a PLA/PLGA blend. To demonstrate the possible pharmaceutical applicability of the microparticle printing technique, the approved peptides ciclosporin A and octreotide were formulated, producing low-density microparticles that showed between sustained release over several months. The facile scale-up of the technique was demonstrated by using an array of 256 ink-jet nozzles, allowing over 1million discrete particles per second to be produced. The new apparatus and methods described herein could be used across a wide range of biomaterials and therapeutic compounds.

      PubDate: 2017-03-27T13:49:58Z
  • Methodology to estimate the yield stress applied to ultraconcentrated
           detergents as model systems
    • Abstract: Publication date: 20 July 2017
      Source:Chemical Engineering Science, Volume 166
      Author(s): N. Calero, J. Santos, J. Muñoz
      Two commercial highly-concentrated detergents have been studied as model systems in order to estimate the yield stress using different methodologies. Both exhibit clear viscoelastic properties with long relaxation times; the elastic component being dominant on the viscous one. They show different yield stress and time-dependent flow properties. While one of them exhibits apparent thixotropy, the other shows a thixotropy/antithixotropy transition, which predicts the occurrence of complex shear-induced microstructural transitions and the need to strict process control. Their flow curves illustrate the different fluidity of both gel detergents, which show standard shear thinning and “very shear thinning” properties, respectively.
      Graphical abstract image

      PubDate: 2017-03-27T13:49:58Z
  • Flow velocity dependence of the pressure drop of oil mist filters
    • Abstract: Publication date: 20 July 2017
      Source:Chemical Engineering Science, Volume 166
      Author(s): H.E. Kolb, J. Meyer, G. Kasper
      The dependence of the differential pressure drop Δ p and the level of internal oil saturation S on the flow velocity of the air were investigated experimentally for a typical oil mist filter composed of oleophilic glass microfiber layers. Over a wide range of filter face velocities ( v =5–70cm/s) and liquid loading rates ( R =15–125 mg / ( m 2 s ) ), and within the accuracy of the measurements, the “wet” pressure drop of the filter Δ p - Δ p 0 (i.e. the increase in Δ p over the “dry” pressure drop Δ p 0 ) was constant and did not show a systematic dependence on v . When decomposing the wet pressure drop into its components Δ p -jump and channel- Δ p , the Δ p -jump was also independent of the oil loading rate. The level of internal liquid saturation S was inversely proportional to v , with an empirical fit function S = 1 / ( 1 + v / v ∗ ) . The characteristic velocity v ∗ was found to depend on the oil loading rate, and presumably also depends on the media structure which was not varied here. This filter behavior is consistent with the “jump-and-channel” model proposed recently by Kampa et al. (2014). The experiments further showed that the “steady-state” pressure drop under constant filter operating conditions underwent a gradual increase with time (termed “ Δ p -creep”) that depends on operating conditions. This Δ p -creep diminishes gradually and was found to become stronger with increasing loading rate and filter face velocity. At the highest rate of increase (i.e. v =70cm/s, R =125 mg / ( m 2 s ) ), an experiment lasting for 1100h did not suffice to attain an asymptotic level for Δ p . Creep was found to be associated with a gradual increase in saturation and must therefore be classified as an(other) instability phenomenon in oil mist filters.

      PubDate: 2017-03-27T13:49:58Z
  • Subspace decomposition and critical phase selection based cumulative
           quality analysis for multiphase batch processes
    • Abstract: Publication date: 20 July 2017
      Source:Chemical Engineering Science, Volume 166
      Author(s): Yan Qin, Chunhui Zhao, Xuezhong Wang, Furong Gao
      Quality analysis and prediction have been of great significance to ensure consistent and high product quality for chemical engineering processes. However, previous methods have rarely analyzed the cumulative quality effect which is of typical nature for batch processes. That is, with time development, the process variation will determine the final product quality in a cumulative manner. Besides, they cannot get an early sense of the quality nature. In this paper, a quantitative index is defined which can check ahead of time whether the product quality result from accumulation or the addition of successive process variations and cumulative quality effect will be addressed for quality analysis and prediction of batch processes. Several crucial issues will be solved to explore the cumulative quality effect. First, a quality-relevant sequential phase partition method is proposed to separate multiple phases from batch processes by using fast search and find of density peaks clustering (FSFDP) algorithm. Second, after phase partition, a phase-wise cumulative quality analysis method is proposed based on subspace decomposition which can explore the non-repetitive quality-relevant information (NRQRI) from the process variation at each time within each phase. NRQRI refers to the quality-relevant process variations at each time that are orthogonal to those of previous time and thus represents complementary quality information which is the key index to cumulatively explain quality variations time-wise. Third, process-wise cumulative quality analysis is conducted where a critical phase selection strategy is developed to identify critical-to-cumulative-quality phases and quality predictions from critical phases are integrated to exclude influences of uncritical phases. By the two-level cumulative quality analysis (i.e., phase-wise and process-wise), it is feasible to judge whether the quality has the cumulative effect in advance and thus proper quality prediction model can be developed by identifying critical-to-cumulative-quality phases. The feasibility and performance of the proposed algorithm are illustrated by a typical chemical engineering process, injection molding.

      PubDate: 2017-03-27T13:49:58Z
  • Optimized design and operation strategy of a CaCu chemical looping process
           for hydrogen production
    • Abstract: Publication date: 20 July 2017
      Source:Chemical Engineering Science, Volume 166
      Author(s): J.R. Fernández, J.C. Abanades
      This work describes the performance of an improved CaCu looping process designed to produce H2 and/or power from natural gas while generating CO2 suitable for reuse and/or permanent storage. The core of the process relies on an arrangement whereby fixed-bed reactors perform adiabatically. A sequence of five stages: sorption enhanced reforming (SER), Cu oxidation, solid/gas heat exchange, CuO reduction/CaCO3 calcination and steam methane reforming (SMR) is used. A continuous flow rate of O2-depleted gas is produced at a sufficiently high pressure and high temperature to drive a gas turbine for the generation of power. The new process design allows the number of reactors to be reduced from the 15 originally proposed in the original scheme to only five. The energy requirements for the reduction/calcination step can be reduced by using the PSA off-gas from the H2 purification step and the syngas generated in a SMR stage. This also allows a reduction of the Cu/Ca molar ratio in the bed to a value of around 2. A dynamic reactor model partially validated in a previous work was used to simulate in detail a complete cycle of the CaCu loping process under large-scale conditions. The simulations show that the progression of the reaction and heat exchange fronts can be regulated by the partial recirculation of the product gases. A process design for a base case with a reference output of 30,000Nm3/h of pure H2 (88.5MWth), which is the typical production of fired tubular reformers installed in refineries, shows that reactors 6m long with an inner diameter of 3m would be sufficient to carry out the entire process, assuming a cycle duration of 15min and a maximum drop in inlet pressure of 10% per stage. A hydrogen production efficiency of 77% is achievable, which is 6 net points above the efficiency of benchmarks based on fired tubular reformers that use amines (MDEA) to remove the CO2. A CO2 capture efficiency of about 95% is obtained, which is 10 net points higher than the values typically estimated for reference H2 plants that use MDEA absorption.
      Graphical abstract image

      PubDate: 2017-03-27T13:49:58Z
  • Experimental investigation of liquid distribution in a packed column with
           structured packing under permanent tilt and roll motions using electrical
           resistance tomography
    • Abstract: Publication date: 20 July 2017
      Source:Chemical Engineering Science, Volume 166
      Author(s): Yongho Son, Gwagin Kim, Sangyoon Lee, Huiyong Kim, Kwangjoon Min, Kwang Soon Lee
      Liquid distribution in a pilot-scale packed column under offshore conditions was experimentally measured and investigated. An experimental column with an inner diameter of 0.4m and a packed height of 4m was built on a sloshing machine that can simulate offshore conditions. A method of electrical resistance tomography combined with electrical impedance and diffuse optical tomography reconstruction software (ERT-EIDORS) was proposed and used to simultaneously measure the liquid distribution at multiple axial positions in the packed column. Validation experiments for the reliability of the ERT-EIDORS method were conducted first. Then the effects of the liquid load, gas factor, and liquid properties on the liquid distribution were investigated under various offshore conditions using the proposed method. For offshore conditions, three permanent tilt angles and four roll motions were considered. The results are presented in terms of the maldistribution factor in most cases and also the 3D plot for selected demonstration cases.

      PubDate: 2017-03-27T13:49:58Z
  • Life cycle cost analysis of MEG regeneration process incorporating a
           modified slip stream concept
    • Abstract: Publication date: 20 July 2017
      Source:Chemical Engineering Science, Volume 166
      Author(s): Hyunho Kim, Youngsub Lim, Yutaek Seo, Minsu Ko
      This study proposes a modified concept for mono ethylene glycol (MEG) regeneration process to prevent the precipitation of monovalent salt (NaCl) and to economize on efficient energy use with operational flexibility. Two-stage distillation was that the second distillation column was operated after the removal of the monovalent salt while controlling the performance of the first distillation column. This modified concept was evaluated according to (i) the possibility of salt precipitation in the re-boiler of the column at various salinity in the produced water (35–224g/L) and (ii) the economic feasibility compared to a conventional concept where water is evaporated off using a single stage distillation column. The salt precipitation was investigated using the ENRTL-RK property in ASPEN PLUS. The conventional concept showed a high risk of NaCl precipitation in the column when the feed stream contains a high salinity. The modified concept showed few precipitation in the column with a high salinity in feed stream. Then, ASPEN PLUS economic analyzer were used to construct the economic evaluation according to the Life Cycle Cost (LCC) methodology including CAPEX and OPEX. The modified concept showed 9.8% decrease in CPAEX and 8.6% decrease in OPEX compared to the conventional concept. The sensitivity analysis showed that the inlet flow rate and the concentration of rich MEG were the most significant factors that affected the economic viability of the MEG regeneration process, and the modified concept was less sensitive to the inlet condition change than the conventional concept.

      PubDate: 2017-03-27T13:49:58Z
  • Rapid salinity measurements for fluid flow characterisation using minimal
           invasive sensors
    • Abstract: Publication date: 20 July 2017
      Source:Chemical Engineering Science, Volume 166
      Author(s): Timm Steffen Severin, Sebastian Plamauer, Andreas Christoph Apel, Thomas Brück, Dirk Weuster-Botz
      For the hydrodynamic characterisation of reactors handling aqueous liquids, especially in conjunction with the validation of numerical simulations, data with high temporal resolution is essential. This paper describes the design of a rapid, flat, and low-cost sensor array for parallel salinity measurements, which allows to perform the required measurements in nearly any reactor type with minimal impact on the flow characteristics due to its very thin (125μm) and flexible structure. Sample measurements for the sensor array system are shown using a step change in aqueous salinity and the resulting response of a thin-layer cascade algae reactor unit as well as performing measurements of a pulse in salinity in the circularly operated algae reactor containing a feedback loop. The system’s response, mixing, and cycle time can be easily extracted from the generated data sets. The sensors provide measurements with an accuracy of about 2% for a linear range of 0–10gl−1 NaCl solution. In its default configuration one device consists of up to eight sensors, which are distributed on two stripes (220×25mm, 125μm thick) each containing four sensor spots, that are positioned 5cm apart from each other. The modular set up of the sensor array facilitates simple modification depending on individual requirements.
      Graphical abstract image

      PubDate: 2017-03-27T13:49:58Z
  • An integrative multiphase model for cancer cell migration under influence
           of physical cues from the microenvironment
    • Abstract: Publication date: 29 June 2017
      Source:Chemical Engineering Science, Volume 165
      Author(s): Steinar Evje
      More than forty years ago Keller and Segel presented a mathematical continuum model for cell migration where chemotaxis was a main transport mechanism together with dispersion. A decade ago Chaplain and Lolas developed a model for cancer cell migration which also accounted for transport due to interaction of cells with fibers in the extracellular matrix (ECM), the so-called haptotaxis effect. Recent cancer research emphasizes the role played by physical cues from the tumor microenvironment besides the biochemical cues. Some of them are: (i) the role of cell-cell and cell-ECM adhesion; (ii) pattern formation caused by detachment of small cell clusters from the primary tumor; (iii) elevated pressure associated with the primary tumor and interstitial fluid flow; (iv) physical resistance forces from the surrounding ECM. Hence, there is a need for mathematical frameworks that can properly integrate all these aspects in a coherent formulation. We apply a multiphase continuum-based approach and consider the cancer cells and interstitial fluid as two distinct compressible phases whereas the ECM is a non-mobile component. The principle of mass and momentum balance are employed such that proliferation, apoptosis, cell force-generating mechanisms, capillary pressure and surface tension (which represent cell-cell and cell-ECM adhesion), as well as resistance forces from the microenvironment can be accounted for. We test the model for different scenarios and compare with reported experimental observations in 2D and 3D. We find that the proposed multiphase model is general enough to adequately address the above mentioned issues (i)–(iv).

      PubDate: 2017-03-27T13:49:58Z
  • Developing breakage models relating morphological data to the milling
           behaviour of flame synthesised titania particles
    • Abstract: Publication date: 20 July 2017
      Source:Chemical Engineering Science, Volume 166
      Author(s): Casper Lindberg, Jethro Akroyd, Markus Kraft
      A detailed population balance model is used to relate the reactor conditions of flame synthesised titanium dioxide particles to their milling behaviour. Breakage models are developed that utilise morphological data captured by a detailed particle model to relate the structure of aggregate particles to their size-reduction behaviour in the post-synthesis milling process. Simulations of a laboratory-scale hot wall reactor are consistent with experimental data and milling curves predicted by the breakage models exhibit features consistent with experimental observations. The selected breakage model considers the overall fractal structure of the aggregate particles as well as the neck size between neighbouring primary particles. Application of the model to particles produced under different reactor residence times and temperatures demonstrates that the model can be used to relate reactor conditions to the milling performance of titanium dioxide particles.
      Graphical abstract image

      PubDate: 2017-03-20T15:56:33Z
  • Highly selective hydrogenation of phenol to cyclohexanol over MOF-derived
           non-noble Co-Ni@NC catalysts
    • Abstract: Publication date: 20 July 2017
      Source:Chemical Engineering Science, Volume 166
      Author(s): Aiqin Li, Kui Shen, Junying Chen, Zhong Li, Yingwei Li
      The selective hydrogenation of phenol is an attractive routine to produce cyclohexanol that is an important basic chemical raw in chemical industry, but the design of cost-efficient and highly selective catalysts remains a great challenge. Herein, we report the first example of non-noble bimetallic nanocatalysts for the selective hydrogenation of phenol with cyclohexanol as the sole product. These catalysts consisting of bimetallic Ni-Co alloy nanoparticles (NPs) encapsulated in N-doped carbon matrix were simply synthesized by using our previously developed MOF-templated strategy (Long et al., 2016). The sum of characterization results revealed that the Co and Ni elements were successfully alloyed in every individual NPs that were confined by N-doped carbon layers. Detailed catalytic test results suggested that both the pyrolysis temperature and the composition of these alloy NPs played the key roles in guiding their catalytic performance in the selective hydrogenation of phenol. It has been shown that Co-Ni@NC system was much more effective for hydrogenation of phenol than Cu@NC, Co-Cu@NC and Ni-Cu@NC systems. The optimal 1Co-1Ni@NC could completely catalyze the hydrogenation of phenol to >99.9% cyclohexanol with a TOF of 0.21h−1, which was approximately 2.8- and 4.3-fold higher than that of the Co@NC and Ni@NC respectively, underscoring a strong positive synergistic effect between Ni and Co for this reaction. The mechanism study revealed the cyclohexanol was formed directly by the one-step hydrogenation of phenol in our catalyst system. This one-step pathway could avoid the formation of other hydrogenated intermediate product thereby leading to >99.9% selectivity of cyclohexanol. Furthermore, this catalyst also showed good recyclability, magnetically reusability and general applicability for a wide range of phenol substrates, which together with the superior activity and selectivity make it a good potential for the industrial applications.
      Graphical abstract image

      PubDate: 2017-03-20T15:56:33Z
  • Hybrid model based expected improvement control for cyclical operation of
           membrane microfiltration processes
    • Abstract: Publication date: 20 July 2017
      Source:Chemical Engineering Science, Volume 166
      Author(s): Lester Lik Teck Chan, Chen-Pei Chou, Junghui Chen
      Membrane fouling can affect the performance of the membrane-based filtration. Fouling thus increases operational costs as a result of permeate flux decline and can be accompanied by increased energy load due to higher transmembrane pressure requirements needed as driving force. This work presents a modeling framework that combines first principle models with Gaussian process model and aims to account for model discrepancy due to the effect of fouling on the system from previous cycle of operation. Based on the expected improvement algorithm, a cycle-to-cycle in conjunction with a within-cycle optimization is proposed to handle the long duration of the operation to achieve the most economical operation in terms of energy load. Simulation studies as well as experimental studies have been carried out to show the applicability of the proposed method.

      PubDate: 2017-03-20T15:56:33Z
  • Catalytic effectiveness of porous particles: A continuum analytic model
           including internal and external surfaces
    • Abstract: Publication date: 20 July 2017
      Source:Chemical Engineering Science, Volume 166
      Author(s): Dror Cohen, Jose Merchuk, Yehuda Zeiri, Oren Sadot
      The well-known pseudo-continuum model of porous catalysts was based on the generally realized assumption that the external surface of the particle is negligible compared to the internal one. While valid for most industrial applications, this assumption may be inapplicable in some cases, especially for micro- to nano-catalytic particles and low internal surface cases. Herein, we developed a descriptive analytic model that explicitly accounts for both the internal and external surfaces. The model correctly describes the two limiting cases of non-porous and highly porous materials. Moreover, we show that by accounting for the external surface, the present model produces substantially different estimation of the catalytic effectiveness compared to that achieved with the traditional pseudo-continuum model.
      Graphical abstract image

      PubDate: 2017-03-20T15:56:33Z
  • Modeling of the interfacial behaviors for the isobutane alkylation with C4
           olefin using ionic liquid as catalyst
    • Abstract: Publication date: 20 July 2017
      Source:Chemical Engineering Science, Volume 166
      Author(s): Weizhong Zheng, Wenxiu Xie, Weizhen Sun, Ling Zhao
      As a typical liquid/liquid interface reaction, the isobutane alkylation with C4 olefins produces C8 alkylates that are important as clean gasoline components. In this work, the interfacial properties between the hydrocarbons (reactants and/or products) and 1-butyl-3-methylimidazolium ionic liquids (ILs) with various anions corresponding to different acidity, including [Bmim][PF6], [Bmim][BF4], [Bmim][AlCl4] and [Bmim][Al2Cl7], have been investigated using molecular dynamics (MD) simulations. The density of the anions of ILs at interface was found to be about 10% higher than that in the bulk, which was favorable to the generation of carbonium at interface. The butyl groups of the cations tend to orient themselves perpendicular to the interface and protrude into the hydrocarbon mixtures phase, enhancing the dissolution of reactants at interface. It was also revealed that for the reactants, the molar fraction of 2-butene both in the bulk and at interface was much higher than that of isobutane, and 2-butene also had a larger diffusion coefficient at interface. However, for the product systems (isobutane+isooctane+IL), both the molar fraction and the diffusion coefficient of isobutane were obviously higher than that of isooctane. Compared to the neutral ILs, for the acidic ILs the binary hydrocarbon mixtures were easier to disperse into the IL phase with the mole fraction nearly 4 times higher in the bulk and about 1.2 times higher at interface. The difference in interfacial properties for various hydrocarbon-IL systems is in good agreement with the interaction energy between the hydrocarbons and the cations, as well as the anions of the ILs. Hopefully, the information concerning the IL-hydrocarbon interface at the molecular level obtained in this work can bring helpful insights into the C4 alkylation process catalyzed by the ILs.

      PubDate: 2017-03-20T15:56:33Z
  • Interaction of bubbles rising inline in quiescent liquid
    • Abstract: Publication date: 20 July 2017
      Source:Chemical Engineering Science, Volume 166
      Author(s): M. Gumulya, R.P. Utikar, G.M. Evans, J.B. Joshi, V. Pareek
      In the buoyant rise of two bubbles arranged in an inline configuration, the trailing bubble tends to accelerate beyond its terminal velocity, due to its interaction with the wake of the preceding bubble. It is demonstrated that several different interactive behaviours could be obtained due to this acceleration. Firstly, at low values of Reynolds numbers ( Re = ρ l V t D / μ ⩽ 35 ) , the inline configuration was found to be stable, and the two bubbles would collide and coalesce due to the velocity difference between the two. Secondly, at higher Re values (Re >50), vorticity development around the trailing bubble causes it to deviate away from the inline configuration, thus preventing the occurrence of a head-on collision between the two bubbles. The deviation of the bubble was found occur if a certain critical velocity is exceeded by the trailing bubble. The value of the critical velocity was found to decrease with increasing Re values. Further, an increase in Eotvos number ( Eo = ρ l gD 2 / σ ) tends to increase the critical velocity, indicating that enhanced bubble deformability actually improves the path stability of the trailing bubble. The interaction of bubbles can therefore significantly influence the tendency of the bubbles to collide and coalesce.

      PubDate: 2017-03-15T15:50:46Z
  • A combined CFD simulation of Plateau borders including films and
           transitional areas of liquid foams
    • Abstract: Publication date: 20 July 2017
      Source:Chemical Engineering Science, Volume 166
      Author(s): Abdolhamid Anazadehsayed, Jamal Naser
      An integrated computational fluid dynamics model is developed for a combined simulation of Plateau borders, films, and transitional areas between the film and the Plateau borders to reduce the simplifications and shortcomings of available models for foam drainage in micro-scale. Additionally, the counter-flow related to the Marangoni effect in the transitional area is investigated. The results of this combined model show the contribution of the films, the exterior Plateau borders, and Marangoni flow in the drainage process more accurately since the inter-influence of foam’s elements is included in this study. The exterior Plateau borders flow rate can be four times larger than the interior ones. The exterior bubbles can be more prominent in the drainage process in cases where the number of the exterior Plateau borders increases due to the geometry of container. The ratio of the Marangoni counter-flow to the Plateau border flow increases drastically with an increase in the mobility of air-liquid interface. However, the exterior bubbles follow the same trend with much less intensity since typically, the flow is less dependent on the interface of air-liquid in the exterior bubbles. Moreover, the Marangoni counter-flow in a near-wall transition area is less important than an internal one. The influence of air-liquid interface mobility on the average velocity of interior foams is attained with more accuracy with more realistic boundary condition. Then it has been compared with other numerical and analytical results. The contribution of films in the drainage is significant for the mobile foams as the velocity of flow in the film has the same order of magnitude as the velocity in the Plateau border. Nevertheless, for foams with rigid interfaces, film’s contribution in foam drainage is insignificant, particularly for the films near the wall of the container.
      Graphical abstract image

      PubDate: 2017-03-15T15:50:46Z
  • Film formation in a horizontal twin-shaft rotating disk reactor for
           polymer devolatilization
    • Abstract: Publication date: 20 July 2017
      Source:Chemical Engineering Science, Volume 166
      Author(s): Wenkai Cheng, Jiajun Wang, Xueping Gu, Lianfang Feng
      Film formation characteristics in a horizontal twin-shaft rotating disk reactor for polymer devolatilization have been investigated by means of experiment and computational fluid dynamics (CFD). Volume of fluid (VOF) model has been used to simulate the film formation process and predict the film thickness distribution on the rotating disks, validated experimentally by electrical conductance method. The mechanism for the film formation in twin-shaft rotating disk reactor is different from that in single-shaft reactor, due to the effect of overlapping zone between two adjacent disks. There are two kinds of films generated in the reactor. The free film, greatly affected by the liquid viscosity and rotating speed, shows the similar characteristics with that in the single-shaft reactor. The scraped film, generated by overlapping zone, is much thinner and more uniform than the free film for highly viscous liquid. Compared with the viscosity and the rotating speed, the disk clearance plays a more significant role in determining the thickness and the shape of the scraped film.
      Graphical abstract image

      PubDate: 2017-03-15T15:50:46Z
  • A coupled Volume of Fluid and Immersed Boundary Method for simulating 3D
           multiphase flows with contact line dynamics in complex geometries
    • Abstract: Publication date: 20 July 2017
      Source:Chemical Engineering Science, Volume 166
      Author(s): H.V. Patel, S. Das, J.A.M. Kuipers, J.T. Padding, E.A.J.F. Peters
      A numerical methodology is presented for simulating 3D multiphase flows through complex geometries on a non-body conformal Cartesian computational grid. A direct forcing implicit immersed boundary method (IBM) is used to sharply resolve complex geometries, employing the finite volume method (FVM) on a staggered grid. The fluid-fluid interface is tracked by a mass conservative sharp interface volume of fluid (VOF) method. Contact line dynamics at macroscopic length scale is simulated by imposing the apparent contact angle (static or dynamic) as a boundary condition at the three-phase contact line. The developed numerical methodology is validated for several test cases including the equilibrium shape of a droplet on flat and spherical surfaces, the temporal evolution of a droplet spreading on a flat surface. The obtained results show an excellent correspondence with those derived analytically or taken from literature. Furthermore, the present model is used to estimate, on a pore-scale, the residual oil remaining in idealized porous structures after water flooding, similar to the process used in enhanced oil recovery (EOR).

      PubDate: 2017-03-15T15:50:46Z
  • Enhancing evaporative mass transfer and steam stripping using microwave
    • Abstract: Publication date: 29 June 2017
      Source:Chemical Engineering Science, Volume 165
      Author(s): O. Ogunniran, E.R. Binner, A.H. Sklavounos, J.P. Robinson
      The effect of microwave heating on evaporative mass transfer of hydrocarbons was investigated for a number of contaminated solid materials. The rate of oil removal could be rationalised by the velocity of steam that was created by selective heating of water within the solid. A single correlation was found to fit 45 independent experiments across 10 separate variables, and the correlation was consistent with the physics of evaporative mass transfer. It is shown for the first time that steam stripping is the dominant mechanism that governs hydrocarbon removal during microwave processing. It was further discovered that mass transfer is enhanced due to microwave heating when compared to conventional stripping processes, with this improvement in efficiency due to the ability of the microwave process to overcome the channelling effects that limit conventional mass transfer processes.
      Graphical abstract image

      PubDate: 2017-03-15T15:50:46Z
  • Airflow and particle transport simulations for predicting permeability and
           aerosol filtration efficiency in fibrous media
    • Abstract: Publication date: 29 June 2017
      Source:Chemical Engineering Science, Volume 165
      Author(s): P.-C. Gervais, D. Bémer, S. Bourrous, L. Ricciardi
      In this work, synchrotron X-ray microtomography was used to produce high spatial resolution images of two kinds of binderless and monodisperse fibrous filter media, made of fiberglass and sintered stainless steel respectively. Representative computational domains were created based on these images. Both flow and collection efficiency simulations were then carried out using the flow and particle transport modules of the GeoDict ® code. An image analysis program based on Matlab ® was used to determine the structural properties of the computational domain, namely the thickness, the solid volume fraction and the fiber size distribution. In parallel, permeability and collection efficiency measurements were performed on the same media, to provide an experimental comparison. Very good agreement was found between the experimental and the simulated permeability values. We showed that, in order to compare collection efficiency from experiments with those simulated with GeoDict ® , it was necessary to take into account the difference between the thickness of the fibrous structures that were used to create the calculation domain, and the averaged experimental thickness characterized by SEM. Using this way of comparison, we obtained the first experimental validation of the GeoDict® code on both permeability and efficiency aspects for aerosols filtration.

      PubDate: 2017-03-15T15:50:46Z
  • Modeling of the electrocoagulation process: A study on the mass transfer
           of electrolysis and hydrolysis products
    • Abstract: Publication date: 29 June 2017
      Source:Chemical Engineering Science, Volume 165
      Author(s): Jun Lu, Zhongru Wang, Xiaoyun Ma, Qing Tang, Yan Li
      Electrocoagulation (EC) which is characterized by in-situ generation of coagulant and hydroxide flocs with high absorption ability is an environmental-friendly process for treating wastewater with heavy metal ions and toxic organics. In order to get a systematic understanding of EC process, a steady state model considering electrochemical, hydrolysis reaction, mass and momentum transfer was established. The coagulant (Al3+), H+ and OH− are generated at the direction of streamline. However, the concentration of these species increases and reaches its maximum near inlet and after that they decrease gradually to a much lower level. We found that there are three areas in EC channel: acid front, base front and buffering area, which has also been found in electro-kinetic remediation. At the direction of streamline, the electro-generated Al3+ is gradually hydrolyzed to hydroxides. The anionic and cationic hydroxides accumulate in acid front and base front respectively. The insoluble hydroxides will accumulate in buffering area, which could be considered as a trap for hydroxide flocs and pollutants.
      Graphical abstract image

      PubDate: 2017-03-15T15:50:46Z
  • Numerical study of gravity effects on phase separation in a swirl chamber
    • Abstract: Publication date: 29 June 2017
      Source:Chemical Engineering Science, Volume 165
      Author(s): Chao-Tsung Hsiao, Jingsen Ma, Georges L. Chahine
      The effects of gravity on a phase separator are studied numerically using an Eulerian/Lagrangian two-phase flow approach. The separator utilizes high intensity swirl to separate bubbles from the liquid. The two-phase flow enters tangentially a cylindrical swirl chamber and rotate around the cylinder axis. On earth, as the bubbles are captured by the vortex formed inside the swirl chamber due to the centripetal force, they also experience the buoyancy force due to gravity. In a reduced or zero gravity environment buoyancy is reduced or inexistent and capture of the bubbles by the vortex is modified. The present numerical simulations enable study of the relative importance of the acceleration of gravity on the bubble capture by the swirl flow in the separator. In absence of gravity, the bubbles get stratified depending on their sizes, with the larger bubbles entering the core region earlier than the smaller ones. However, in presence of gravity, stratification is more complex as the two acceleration fields – due to gravity and to rotation – compete or combine during the bubble capture.

      PubDate: 2017-03-15T15:50:46Z
  • Fast mass transport across two-dimensional graphene nanopores: Nonlinear
           pressure-dependent gas permeation flux
    • Abstract: Publication date: 29 June 2017
      Source:Chemical Engineering Science, Volume 165
      Author(s): Chengzhen Sun, Bofeng Bai
      Mass transport across two-dimensional nanopores is very essential to the porous graphene and other atomically thin membranes for gas separation. Due to the contribution of gas adsorption and diffusion over the two-dimensional surfaces, mass transport across graphene nanopores cannot be described only by the kinetic theory of gases. We show that the combination of the linear pressure-dependent direct flux, governed by the kinetic motion of gas molecules, and the nonlinear pressure-dependent surface flux, caused by the Langmuir isothermal adsorption characteristics of gas molecules on the two-dimensional surfaces, results in an overall nonlinear pressure dependence of the gas permeation flux through graphene nanopores. Based on the mass transport resistance network connecting the multiple molecular transport processes in direct flux and surface flux, a theoretical model that captures the pressure dependence of permeation flux is established, offering a possible avenue to predict the mass transport rates through the two-dimensional nanopores.
      Graphical abstract image

      PubDate: 2017-03-15T15:50:46Z
  • Rapid mixing by turbulent-like electrokinetic microflow
    • Abstract: Publication date: 29 June 2017
      Source:Chemical Engineering Science, Volume 165
      Author(s): Wei Zhao, Fang Yang, Kaige Wang, Jintao Bai, Guiren Wang
      Rapid mixing has been achieved in a pressure-driven microflow which is forced under AC electric field. In our previous investigations, the mixing on large scale at the centerline of microchannel has been studied. Here, we show that the evaluation on mixing effect by flow visualization could be misleading, if its temporal resolution is not sufficiently high. By using single-point laser induced fluorescence (LIF) method, the mixing on both large and small scales can be investigated with high spatiotemporal resolution. It is found fast mixing is not only achieved at the centerline, but also in the majority of cross-sectional area, even near the bottom wall region. This is resulted from the large scale secondary flow due to unbalanced AC electroosmotic flow near the bottom wall. The temporal −5/3 spectrum of concentration measured with LIF in our previous investigations is also supported by the spatial spectrum of concentration. The physical process of mixing on small scales is further investigated by the flatness of concentration gradients.

      PubDate: 2017-03-15T15:50:46Z
  • Local investigations on the gas-liquid mass transfer around Taylor bubbles
           flowing in a meandering millimetric square channel
    • Abstract: Publication date: 29 June 2017
      Source:Chemical Engineering Science, Volume 165
      Author(s): Lixia Yang, Karine Loubière, Nicolas Dietrich, Claude Le Men, Christophe Gourdon, Gilles Hébrard
      Gas-liquid mass transfer around Taylor bubbles moving in a meandering millimetric square channel was locally visualized and characterized in the present study. For that, the colorimetric technique proposed by Dietrich et al. (2013) was implemented. With this technique, the evolution of equivalent oxygen concentration fields in the liquid slugs passing through one and several bends was firstly described. In particular, it was observed how the flow structure (recirculation zones) inside the liquid slugs were twisted and split by the periodic bends (centrifugal effect), until reaching, after several bends, a uniform O2 concentration inside the liquid slugs. The influence of the “turning point”, joining two “straight” sections of meandering channel was also highlighted: a slowing down of the gas-liquid mass transfer was clearly shown. Volumetric mass transfer coefficients were determined at last by fitting the experimental axial profiles of averaged oxygen concentrations in the liquid slugs (before the turning point) with the ones predicted by a classical plug-flow model.

      PubDate: 2017-03-15T15:50:46Z
  • Reverse roll coating with a deformable roll operating at negative gaps
    • Abstract: Publication date: 29 June 2017
      Source:Chemical Engineering Science, Volume 165
      Author(s): H. Benkreira, Y. Shibata, K. Ito
      Reverse roll coating is probably the most widely used coating operation, yet its full potential has not been exploited as it is shown in this paper which considers operation with a negative gap. We demonstrate through a wide range of experimental data that such operation can yield very thin and stable films with no ribbing or cascade instabilities when low viscosity fluids are used. Typically, stable film thickness less than 5μm can be obtained at speeds up to 150m/min when a rubber roller is used at −100μm gap with fluids of viscosity in the range 10–200mPas. These film thicknesses can be made to decrease further down to 1 or 2µm with a judicious choice of speed ratios (applicator to metering roller) and rubber hardness. Such new findings make this simple coating method an attractive roll to roll technique for application in the newer coating technologies, such as in the production of solar cells and plastic electronics. The data obtained in this study have been underpinned by a model based on the classical lubrication theory, well developed for such flow situations. Essentially it is shown that the film thickness non dimensionalised with respect to the set negative gap is controlled through a single parameter, the elasticity number Ne which combines all the operating parameters. Of course, this flow problem has complexities, particularly at high speed ratios and at zero gap so the data obtained here can serve as a basis for more comprehensive modelling of this classical fluid mechanic problem.
      Graphical abstract image

      PubDate: 2017-03-15T15:50:46Z
  • Stability of gravity-driven free surface flow of surfactant-laden liquid
           film flowing down a flexible inclined plane
    • Abstract: Publication date: 29 June 2017
      Source:Chemical Engineering Science, Volume 165
      Author(s): Dharmendra S. Tomar, Mahendra Baingne, Gaurav Sharma
      We examined the linear stability of gravity-driven creeping flow of a liquid film flowing down an inclined plane when the inclined plane is coated with a deformable solid layer and the gas-liquid interface is contaminated with a monolayer of insoluble surfactant. The contaminated liquid film flowing down a rigid incline admits gas-liquid (GL) interfacial mode and surfactant-induced Marangoni mode, both of which remain stable in the creeping flow limit. The primary aim of this study is to explore the effect of the presence of a deformable wall, in place of a rigid inclined wall, on the stability behavior of Marangoni mode which originates because of the transport of surfactant at the GL interface. In presence of a deformable solid layer, two additional parameters namely, shear modulus and thickness of deformable solid layer also affects the stability behavior of falling film configuration. Our long-wave asymptotic analysis and results at finite and arbitrary wavenumbers demonstrated the destabilization of Marangoni mode solely due to the presence of deformable solid layer. Specifically, we have shown that for a given solid thickness, the Marangoni mode becomes unstable when the shear modulus of solid layer decreases below a critical value (i.e. the solid layer becomes sufficiently soft). The effect of increasing solid thickness is found to be destabilizing. The LS interfacial mode also becomes unstable at high wavenumbers below a threshold value of shear modulus, however, this value is much smaller than that required to trigger Marangoni mode instability. This implies that as the solid coating becomes more and more deformable, the Marangoni mode becomes unstable first followed by the LS interfacial mode. The GL mode was always found to be stable in creeping flow limit. Further, our long-wave analysis shows that the solid deformability has an additional stabilizing effect on GL mode. The neutral stability curves in nondimensional solid deformability parameter (or equivalently shear modulus) vs. wavenumber plane clearly depicts that the Marangoni mode is the dominant unstable mode in the creeping flow limit. Thus, the present study shows the destabilization of Marangoni mode solely due to presence of deformable solid layer and this we believe is the first example of the case where the instability of the Marangoni mode is observed when the fluid-fluid interface (here, GL interface) remains stress-free in the basic state.

      PubDate: 2017-03-15T15:50:46Z
  • Transport and removal of a solvent in porous media in the presence of
           bitumen, a highly viscous solute
    • Abstract: Publication date: 29 June 2017
      Source:Chemical Engineering Science, Volume 165
      Author(s): Siddhant Panda, Krupal Pal, Sumeet Merzara, Murray R. Gray, Qi Liu, Phillip Choi
      Removal of solvent from the gangue generated by an oil sands solvent extraction process is essentially a process of solution transport in a porous medium with a highly viscous solute (left over bitumen of a completed extraction process or residual bitumen) at low concentrations. The solvent usually has much higher vapor pressure and lower viscosity than the residual bitumen. The concentrations of the residual bitumen are typically in the range of 0.6–2.4wt% while those of the solvent (cyclohexane) is 8–12wt% at the start of the drying process to remove the solvent. Drying of gangue was carried out for 2h under ambient conditions using petri dishes with bed heights of 0.6, 1.0 and 1.4cm. A typical drying curve (i.e., cumulative volatiles mass loss versus time) shows two distinct drying stages in which the first stage is the fast evaporation of cyclohexane (99% by weight removal) followed by a stage in which slow evaporation of water is observed. The residual bitumen was observed, unexpectedly, to migrate to the top surface of the porous media with cyclohexane via capillary transport and accumulate there in the first stage of drying. The rate of removal of cyclohexane decreased with increasing residual bitumen content. Consequently, duration of the fast cyclohexane removal stage from the gangue sample containing 2.4wt% bitumen was 1.5 times longer than that of the 0.6wt% bitumen gangue sample, when the initial cyclohexane concentration was 12wt%; it was 1.2 times longer when the initial cyclohexane concentration was 8wt%. Our studies reveal that poor capillary transport of solution in porous media at higher bitumen concentrations to be the most likely cause of slower drying rather than vapor pressure lowering of bulk solution and pores blockage. The cause is similar to previous reports in literature with the solute being salt in salt-water solution.

      PubDate: 2017-03-15T15:50:46Z
  • Enzymatic reactive crystallization for improving ampicillin synthesis
    • Abstract: Publication date: 29 June 2017
      Source:Chemical Engineering Science, Volume 165
      Author(s): Matthew A. McDonald, Andreas S. Bommarius, Ronald W. Rousseau
      The enzyme penicillin G acylase (PGA) catalyzes the condensation of phenylglycine methyl ester (PGME) with 6-aminopenicillanic acid (6-APA) to form ampicillin. We improved the selectivity of ampicillin synthesis with PGA by running simultaneous reaction and crystallization. However, the enzyme also catalyzes two undesirable side reactions: the hydrolysis of PGME to phenylglycine and the hydrolysis of ampicillin to phenylglycine and 6-APA. We demonstrate that a fifty percent improvement in selectivity for ampicillin over phenylglycine is achieved by combining reaction and crystallization in batch at pH value of 6 with saturated 6-APA and equimolar PGME. The enhancement in selectivity is mainly attributed to the decreased rates of enzymatic ampicillin hydrolysis; however, the course of the pH value during the reaction also has an effect on enzyme activity that improved selectivity. In addition to showing experimental results, we developed a new kinetic process model that predicts the observed improvement. The new model accounts for the solubility limits of different species as functions of pH value as well as the large change in pH value at high conversion. Previous work does not account for changes in activity with conversion. The pH-dependent activity for the specific enzyme used in this system, Assemblase® from DSM-Sinochem, is well-realized by the model and generalization to other PGAs is possible within the model framework; the selectivity parameters α, β0, and γ for Assemblase® are compared to PGA from E. coli as evidence.

      PubDate: 2017-03-08T20:33:10Z
  • Predominant mode of diesel uptake: Direct interfacial versus
           emulsification in multiphase bioreactor
    • Abstract: Publication date: 29 June 2017
      Source:Chemical Engineering Science, Volume 165
      Author(s): O. Angeles, S.A. Medina-Moreno, A. Jiménez-González, A. Coreño-Alonso, M.A. Lizardi-Jiménez
      Hydrocarbon uptake by microorganisms in a multiphase bioreactor can be carried out by two mechanisms: direct interfacial contact of microorganisms with hydrocarbon drops or emulsified microdroplet uptake. Most previous studies have considered uptake mediated by biosurfactants to be the predominant mode of uptake, but scarce experimental information is available about which mechanism actually prevails. The aim of this work was to evaluate the predominant mode of diesel uptake in multiphase bioreactors. In the absence of emulsifiers in bioreactor, day 0 to day 2 of culture time of oil–degrading consortium composed of three bacterial genera: Pseudomonas, Vibrio and Diplococcus, 6870mgL−1 of diesel was consumed, which can only be explained by direct interfacial contact. In the presence of emulsifiers, at a superficial gas velocity (Ug) of 2cms−1 from day 5 to day 7, 3460mgL−1 of diesel was consumed and the maximum diesel transfer rate (DTR) (16.3mgL−1 h−1) for this Ug could only explain 782.4mgL−1 of diesel uptake. Our study reveals that strategies focused only on mass transfer may not be sufficient to design multiphase bioreactors since direct interfacial, not emulsification, is the predominant mode of diesel uptake.

      PubDate: 2017-03-08T20:33:10Z
  • Exploiting kinetics to unravel the role of a ZnO diluent in the production
           of CO via oxidizing Zn particles with CO2
    • Abstract: Publication date: 29 June 2017
      Source:Chemical Engineering Science, Volume 165
      Author(s): David Weibel, Zoran R. Jovanovic, Aldo Steinfeld
      Direct oxidation of pure Zn particles with CO2 is inhibited by an impervious ZnO scale. The presence of a ZnO diluent surface provides a site for an additional heterogeneous reaction of sublimated Zn that allows for a fast and high conversion of Zn. This is relevant to the efficient production of CO by the oxidation of Zn particles produced by the solar thermal dissociation of ZnO that are generally contaminated by the recombined ZnO. The overall reaction mechanism thus involves the sublimation of Zn(g) from the Zn surface, its transport to the ZnO diluent surface, and its subsequent heterogeneous reaction with CO2 on this surface. To elucidate the most relevant of those elementary steps different kinetic models were tested against a broad set of isothermal thermogravimetric data acquired at different temperatures, CO2-concentrations, and initial ZnO contents. The overall rate was found to be controlled by the transport of Zn(g) to the ZnO diluent surface and the reaction of the chemisorbed CO2 either with Zn(g) or with Zn incorporated from gas phase into the ZnO lattice surface sites. Increasing the initial content of ZnO diluent increases the effectiveness of the heterogeneous reaction at the ZnO diluent surface which facilitates the sublimation of Zn and appears to render the ZnO product scale surrounding unreacted Zn more permeable.
      Graphical abstract image

      PubDate: 2017-03-08T20:33:10Z
  • Stability and breakup of liquid jets: Effect of slight gaseous crossflows
           and electric fields
    • Abstract: Publication date: 29 June 2017
      Source:Chemical Engineering Science, Volume 165
      Author(s): A. Rajabi, M.R. Morad, N. Rahbari
      Instability and breakup of a liquid jet under the influence of a gaseous crossflow in the presence of an electric field is investigated. A dispersion relation for disturbances on the jet surface is derived for the combined effects based on pioneer linear stability analysis for low speed limits. Effects of Weber, Bond and Ohnesorge numbers on the growth rate of disturbances are studied. The theoretical analysis developed for breakup length is used for comparisons with experimentally obtained breakup lengths. Measured breakup lengths were predicted satisfactorily by the linear theory in the region of low crossflow velocities (0–4m/s) and electric field intensities (0– 3 × 10 5 V/m).

      PubDate: 2017-03-08T20:33:10Z
  • Oxygen-selective adsorption in RPM3-Zn metal organic framework
    • Abstract: Publication date: 29 June 2017
      Source:Chemical Engineering Science, Volume 165
      Author(s): Cheng-Yu Wang, Linxi Wang, Andrew Belnick, Hao Wang, Jing Li, Angela D. Lueking
      Development of an oxygen selective adsorbent is anticipated to reduce the material and energy requirements for adsorptive separations of air by a factor of four, due to the relative concentrations of N2 and O2 in air, thereby decreasing the parasitic energy losses, carbon dioxide emissions, and cost of oxygen purification via pressure-swing adsorption. Here, we report that RPM3-Zn (a.k.a. Zn2(bpdc)2(bpee); bpdc=4,4′-biphenyldicarboxylate; bpee=1,2-bipyridylethene) is oxygen selective over nitrogen at temperatures from 77K to 273K, although the oxygen capacity of the sorbent decreased markedly at increasing temperatures. Due to an oxygen diffusivity that is ∼1000-fold greater than nitrogen, the effective oxygen selectivity increases to near infinity at low temperature at equal contact times due to N2 mass transfer limitations for gate-opening. The kinetic limitation for N2 to open the structure has a sharp temperature dependence, suggesting this effective kinetic selectivity may be “tuned in” for other flexible metal-organic-frameworks. Although the low temperature oxygen selectivity is not practical to displace cryogenic distillation, the results suggest a new mechanism for tailoring materials for kinetic selectivity, namely, capitalizing upon the delayed opening process for a particular gas relative to another.

      PubDate: 2017-03-08T20:33:10Z
  • Modeling flow in porous media with rough surfaces: Effective slip boundary
           conditions and application to structured packings
    • Abstract: Publication date: 29 June 2017
      Source:Chemical Engineering Science, Volume 165
      Author(s): Sylvain Pasquier, Michel Quintard, Yohan Davit
      Understanding and modeling flows in columns equipped with structured packings is crucial to enhance the efficiency of many processes in chemical engineering. As in most porous media, an important factor that affects the flow is the presence of rough surfaces, whether this roughness has been engineered as a texture on the corrugated sheets or is the result of hydrodynamic instabilities at the interface between a gas and a liquid phase. Here, we develop a homogenized model for flows in generic porous media with rough surfaces. First, we derive a tensorial form of an effective slip boundary condition that replaces the no-slip condition on the complex rough structure and captures surface anisotropy. Second, a Darcy-Forchheimer model is obtained using the volume averaging method to homogenize the pore-scale equations with the effective slip condition. The advantage of decomposing the upscaling in these two steps is that the effective parameters at the Darcy-scale can be calculated in a representative volume with smooth boundaries, therefore considerably simplifying mesh construction and computations. The approach is then applied to a variety of geometries, including structured packings, and compared with direct numerical solutions of the flow to evaluate its accuracy over a wide range of Reynolds number. We find that the roughness can significantly impact the flow and that this impact is accurately captured by the effective boundary condition for moderate Reynolds numbers. We further discuss the dependance of the permeability and generalized Forchheimer terms upon the Reynolds number and propose a classification into distinct regimes.

      PubDate: 2017-03-08T20:33:10Z
  • CFD-DEM simulations of a fluidized bed crystallizer
    • Abstract: Publication date: 29 June 2017
      Source:Chemical Engineering Science, Volume 165
      Author(s): Kristin Kerst, Christoph Roloff, Luís G. Medeiros de Souza, Antje Bartz, Andreas Seidel-Morgenstern, Dominique Thévenin, Gábor Janiga
      In the present study, important features of the two-phase flow in a fluidized bed crystallizer are examined by numerical computations and companion experiments. The simulations are carried out using a coupled CFD-DEM approach (CFD: Computational Fluid Dynamics; DEM: Discrete Element Method). After validating an open-source CFD-DEM software tool for this purpose, regions within the crystallizer with unfavorable hydrodynamic features and thus a negatively impacted process outcome have been identified. This was first accomplished by single-phase CFD simulations. Then, the validated CFD-DEM model delivers valuable information that is difficult or even impossible to measure experimentally with sufficient accuracy, such as the velocity and position of fluidized crystals within the crystallizer. Since the simulations are computationally challenging, a compromise between simulated process time and number of simulated particles must be found. Hence, the CFD-DEM simulations are not utilized to simulate the whole crystallization process, but to examine a short time-window in detail. Corresponding findings confirm proper fluidization of the crystals support the model reduction carried out in a parallel project.

      PubDate: 2017-03-02T07:28:36Z
  • Butyric anhydride modified lignin and its oil-water interfacial properties
    • Abstract: Publication date: 29 June 2017
      Source:Chemical Engineering Science, Volume 165
      Author(s): Zhe Zhang, Yi Zhang, Zhaoyun Lin, Arie Mulyadi, Wei Mu, Yulin Deng
      A bio-based surfactant was prepared by chemical modification of kraft lignin. Herein, grafting of butyric anhydride (BA), 3-(trimethoxysilyl)propyl methacrylate (MPS) and 2-bromoisobutyryl bromide (BIBB) onto kraft lignin were conducted to change its amphiphilicity and the chemical reactions were confirmed by FTIR, 1H NMR, GPC, TGA and 31P NMR. The lignin modified with MPS and BIBB was only partially dissolved in organic monomers due to the low grafting ratio. In contrast, over 95% of the hydroxyl group conversion was achieved when BA was used. The BA modified lignin (lignin-B) was found to be completely soluble in the monomers. The interfacial tension measurement indicated the capability of lignin-B to decrease the interface energy between water and styrene from 35Jm−2 to 15Jm−2. As the result, a stable water-in-oil emulsion was achieved using lignin-B as the emulsifier. The average diameters of emulsion droplets were 499.4nm and 363.9nm with a lignin-B content of 0.5wt% and 5wt% respectively. Due to both steric and electrokinetic effects, the as-prepared water-in-oil emulsion was kept stable over 30days. These results suggest that lignin-B has a promising potential to be used as a bio-based surfactant.
      Graphical abstract image

      PubDate: 2017-03-02T07:28:36Z
  • Detailed numerical analysis of evaporation of a micrometer water droplet
           suspended on a glass filament
    • Abstract: Publication date: 29 June 2017
      Source:Chemical Engineering Science, Volume 165
      Author(s): Oluwafemi Ayodele George, Jie Xiao, Carles Safont Rodrigo, Ruben Mercadé-Prieto, Julià Sempere, Xiao Dong Chen
      For a long time, the single droplet drying (SDD) equipment has been utilized to investigate droplet drying behaviour relevant to spray drying. Typical of the device is a global measurement of droplet’s drying kinetics such as evaporation rate, temperature history, diameter changes, etc., and has been extensively used for such purposes. Utilization of computational fluid dynamics (CFD) enables SDD experiment to be interpreted and examined closely as well as for better exploration of the device with views of improving it in future. Here, for the first time, we have provided detailed numerical simulation of the laboratory condition of SDD using a pure water droplet suspended on a glass filament tip. With CFD, it is therefore possible to determine the local flux of vapour or global evaporation rate across the droplet-air interface using the equations of transport. The Arbitrary Lagrangian-Eulerian (ALE) procedure embedded inside Navier-Stokes ensures interface tracking as well as visualization of the droplet shape evolution. As a concrete demonstration of the SDD situations, effects of different glass knob sizes for different sizes of suspended pure water droplet (0.98–1.56mm initial diameter), upward inflow of humid air and temperature (0.01% and 358.15K), and air velocity 1.11ms−1 were examined on evaporation rate; shape formation; flow velocity and temperature distribution within and around the droplet. Our model is based on the first principles, without adjustable parameters, the predictions made are in good agreement with the available experimental SDD data.
      Graphical abstract image

      PubDate: 2017-03-02T07:28:36Z
  • Modelling filtration processes from local filtration properties: The
           effect of surface properties on microcrystalline cellulose
    • Abstract: Publication date: 29 June 2017
      Source:Chemical Engineering Science, Volume 165
      Author(s): Jonas Wetterling, Tuve Mattsson, Hans Theliander
      The influence of structure and charge of particles surfaces on the cake filtration behaviour of microcrystalline cellulose was investigated. The local filtration properties were evaluated experimentally and used to model the overall filtration behaviour. At suspension conditions where the microcrystalline cellulose particles are charged, a large pressure drop was observed close to the filter medium, thereby indicating that a rate-limiting skin layer was formed. Measurements of the local solidosity of the filter cake indicated that a secondary filter cake, with a negligible filtration resistance, formed above the rate-limiting skin layer. This behaviour was not observed when the surface roughness of the particles was increased or when the surface charge of the particles was neutralised by making a change to the pH of the suspension. The filtration behaviour of particles with these surface properties was instead dominated by the formation of a compressible filter cake. Local filtration properties of compressible filter cakes determined experimentally were used to successfully model the overall filtration behaviour. The filtration model used an empirical relationship to describe the pressure dependence of the local solidosity of the filter cake along with a cell model to describe the relationship between the solidosity and the permeability of the filter cake.

      PubDate: 2017-03-02T07:28:36Z
  • Correlations of medium physical properties and process performance in
           solid-state fermentation
    • Abstract: Publication date: 29 June 2017
      Source:Chemical Engineering Science, Volume 165
      Author(s): Yuzhen Zhang, Lan Wang, Hongzhang Chen
      The medium of solid-state fermentation (SSF) is a multiphase system, whose complex physical properties cause difficulties of the cognition of SSF process and the process control. This paper aimed to deeply analyze the mechanical, structural and thermal properties of solid-state medium, explored relationships between the medium’s physical properties and fermentation performance, then to guide the process control and culture medium optimization for SSF. A mechanical property index (Imp ), which was the product of resilience, cohesiveness, and springiness, was established to fully characterize physical properties of medium. Results showed at the initial stage of SSF, there were positive correlations of Imp with thermal conductivity and water retention, negative correlations with gas permeability and thermal diffusivity, and a parabolic relationship with biomass content with a symmetry-axis at Imp =4.37×10−2. Correlations were further verified in SSF dynamic process. During the first 100h, Imp ≤4.37×10−2 was positively correlated with heat conduction and water retention in medium, which was beneficial for cell growth; while when Imp >4.37×10−2 during 100–168h, medium heat accumulation, poor heat diffusivity and poor gas permeability indicated the reduction of fermentation performance. Results revealed medium physical properties significantly affected heat and mass transfer and further influenced fermentation performance in SSF. Mechanical property index Imp could well comprehensively characterize physical properties of medium, which could be useful for guiding initial culture medium preparation and SSF process control.
      Graphical abstract image

      PubDate: 2017-03-02T07:28:36Z
  • A numerical study of cutting bubbles with a wire mesh
    • Abstract: Publication date: 29 June 2017
      Source:Chemical Engineering Science, Volume 165
      Author(s): M.W. Baltussen, J.A.M. Kuipers, N.G. Deen
      Gas-liquid-solid flows are frequently encountered in chemical, petrochemical and biochemical industries. To overcome the heat and mass transfer limitations in trickle bed reactors and bubble slurry columns, respectively, a micro-structured bubble column (MSBC) can serve as an attractive alternative. In a MSBC, wire meshes are introduced to cut the bubbles in smaller bubbles and enhance the surface renewal (and hence gas-liquid mass transfer) rates, by deformation of the bubbles. Earlier (Jain et al., 2013) modeling efforts using the Euler-Lagrange approach to simulate a micro-structured bubble column employed a bubble cutting closure based on purely geometrical considerations. To improve on this ad hoc procedure in this paper we explore the possibilities of Direct Numerical Simulations to gain more insight in this complex phenomenon with the ultimate aim to develop improved closures. A combined Volume of Fluid-Immersed Boundary method was applied to simulate the interactions between bubbles and wire meshes. When the bubbles are aligned with the opening of the wire mesh, cutting of the bubbles is not observed in our simulations, while cutting was expected based solely on geometrical considerations. When the Eötvös number, Eo , is larger than 4, the bubbles are highly deformable and squeeze themselves through the opening of the wire mesh. In addition, the bubble gets stuck underneath the mesh when the bubbles are small ( Eo ⩽ 4 ) and/or the opening is in the wire mesh is small. Almost all bubbles that hit the intersection of two crossing wires get stuck underneath the mesh, except for large bubbles ( Eo = 15 ), which get cut by the mesh. Based on these results, it is concluded that the cutting of bubbles depends on the Eötvös number, the opening of the wire mesh and geometrical considerations. However, the results also seem to indicate that the diameter of the wire mesh will also influence the cutting behavior.

      PubDate: 2017-03-02T07:28:36Z
  • Mass transfer in a pulsed and non-pulsed disc and doughnut (PDD) solvent
           extraction column
    • Abstract: Publication date: 29 June 2017
      Source:Chemical Engineering Science, Volume 165
      Author(s): Yong Wang, Heng Yi, Kathryn H. Smith, Kathryn A. Mumford, Geoffrey W. Stevens
      Mechanical agitation or pulsation is usually introduced to a solvent extraction column to improve the efficiency. Recently a number of industrial scale pulsed disc and doughnut (PDD) solvent extraction columns have been found to have higher extraction efficiency while running with non-pulsing. In this study, the mass transfer performance of a PDD column was measured under pulsing and non-pulsing conditions using a 72.5mm diameter disc and doughnut column. The effects of pulsation intensity and dispersed and continuous phase velocity on the mass transfer performance have been investigated. The results show that, under non-pulsing conditions, the overall mass transfer coefficient increased with increasing continuous phase flow rate and slightly decreased with increasing dispersed phase flow rate. With increasing pulsation intensity, the overall mass transfer coefficient decreased at first and then increased. Two correlations are proposed to predict the height of mass transfer unit and overall mass transfer coefficient in a PDD column including pulsing and non-pulsing conditions.
      Graphical abstract image

      PubDate: 2017-03-02T07:28:36Z
  • Recovery of volatile fatty acids from water using medium-chain fatty acids
           and a cosolvent
    • Abstract: Publication date: 29 June 2017
      Source:Chemical Engineering Science, Volume 165
      Author(s): Marisa A.A. Rocha, Sona Raeissi, Patrick Hage, Wilko M.A. Weggemans, Jaap van Spronsen, Cor J. Peters, Maaike C. Kroon
      The use of industrial waste streams as a source of biomass is beneficial, not only to reduce environmental problems, but also to save valuable resources. Waste streams containing volatile fatty acids (VFAs) are one such example. However, separation from these streams is challenging because of the low concentrations of VFAs found in aqueous solutions. In this study, medium-chain fatty acids (MCFAs) diluted in an organic solvent are used as extractants for VFAs from dilute aqueous solutions. MFCAs have the advantage of forming double hydrogen bonds, which makes them very interesting for the recovery of VFAs. Liquid-liquid extractions (LLE) are carried out using hexanoic, octanoic or decanoic acid as the MFCA extracting agents, diluted with either hexane or toluene for economy. The various VFAs extracted consist of either acetic, propionic or butyric acid. In this manner, the effect of parameters such as the alkyl chain length of the VFAs and MCFAs and the nature of diluent have been investigated. In addition, the influence of the concentration of MCFAs in the diluent (n-hexane and toluene) on the extraction efficiency of the various VFAs has been determined. Results suggest that the decrease in extraction efficiency by diluting an MCFA with a conventional solvent is not at all a linear function of volume fraction. Therefore, a diluted MFCA has the potential to be the more economic extractant rather than a pure MCFA, as very little extraction efficiency is sacrificed over relatively large ranges of dilution.

      PubDate: 2017-03-02T07:28:36Z
  • X-ray imaging of horizontal jets in gas fluidised bed nozzles
    • Abstract: Publication date: 8 June 2017
      Source:Chemical Engineering Science, Volume 164
      Author(s): Luca Panariello, Massimiliano Materazzi, Roberto Solimene, Piero Salatino, Paola Lettieri
      The design of the fluidising air distributors, or nozzles, is one of the most important aspects influencing operation of fluidised beds at industrial scale. In this work, the study of the hydrodynamics in gas-solid fluidized beds where the primary gas injection is achieved through a nozzle-type gas distributor has been carried out, using an innovative X-ray imaging technique. Qualitative and quantitative results are reported, with particular focus on jets penetration length and their evolution. Results show that the lighter and the finer are the particles, the larger is the jet penetration. Since the experimental data do not match predictions available in literature, a new non-dimensional correlation based on hydrodynamic scaling and Froude number is also proposed. The new correlation takes into account the effects of jet velocity, particle density and particle size. A tentative mechanistic explanation for the departure from purely hydrodynamic scaling is offered.

      PubDate: 2017-03-02T07:28:36Z
  • Data-driven model and model paradigm to predict 1D and 2D particle size
           distribution from measured chord-length distribution
    • Abstract: Publication date: 8 June 2017
      Source:Chemical Engineering Science, Volume 164
      Author(s): Roberto Irizarry, Antong Chen, Randolph Crawford, Lorenzo Codan, Jochen Schoell
      A new data-driven model has been developed to determine 1D/2D particle size distribution (PSD) from measured FBRM chord-length distribution (CLD) data. The structure of the model consists of three steps: first, the measured CLDs are compressed down to a small set of parameters; second, these parameters are correlated with low order moments or a small number of percentiles of the PSD using regression models; third, the PSD low order moments are used as input variables, and a two layer-network sub-model is built to predict the PSD in a form of a histogram. Two key aspects of this modeling strategy are noteworthy, namely the construction of specialized parameterized functions (herein called generating functions) that reduce the number of parameters needed to train the model’s two layer network component, as well as its ability to model a 2D size distribution. To demonstratethis paradigm, the model was used to determine the PSD of particles with an elongated morphology. It is shown that even with a limited data set, models could be trained to predict PSD generated by laser diffraction, minor size PSD generated by image analysis, and 2D minor-major PSD measured by image analysis.
      Graphical abstract image

      PubDate: 2017-03-02T07:28:36Z
  • Detailed population balance modelling of TiO2 synthesis in an industrial
    • Abstract: Publication date: 8 June 2017
      Source:Chemical Engineering Science, Volume 164
      Author(s): Astrid Boje, Jethro Akroyd, Stephen Sutcliffe, John Edwards, Markus Kraft
      This paper uses a network of ideal flow reactors and a detailed population balance model to study the evolution of the size and shape distributions of pigmentary titanium dioxide, formed under industrial synthesis conditions. The industrial reactor has multiple reactant injections, a tubular working zone in which the exothermic reaction is completed, and a cooling zone. A network of continuously stirred tank reactors is used to model variation in composition around the feeds and plug flow reactors with prescribed temperature gradients are used to describe the working and cooling zones. The quality of the industrial product depends on its morphology, and this is influenced by factors including temperature and throughput. In this paper, a multivariate particle model is accommodated using a stochastic method and the particle morphology is characterised in terms of the distributions of primary and aggregate particle diameters, number of primary particles per particle and neck radii of connected primary particles. Increasing temperature or residence time is shown to produce larger particles. Qualitative similarities are highlighted between such findings and previous studies. The throughput studies are also in qualitative agreement with empirical industrial experience. There is scope for extending and improving the current model; however, it is suggested that insights of this type could be used to inform the design and operation of the industrial process.
      Graphical abstract image

      PubDate: 2017-03-02T07:28:36Z
  • Artificial vision system for particle size characterization from bulk
    • Abstract: Publication date: 8 June 2017
      Source:Chemical Engineering Science, Volume 164
      Author(s): Pierantonio Facco, Andrea C. Santomaso, Massimiliano Barolo
      This study shows how to develop a fast, reliable, and non-invasive artificial vision system to quantitatively estimate the particle size distribution of granular products. The system, based on multivariate and multiresolution texture analysis, uses digital images of the bulk material to extract quantitative information on the particle size ranges appearing in each image and on their weight proportion independently of the shape of the particle distribution (mono- or multi-modal). The method is applied to a wet-granulated product (namely, microcrystalline cellulose), and it is shown that the size distributions can be estimated accurately. The system performance is discussed in the light of an application in the automated monitoring of particle size distribution in industrial processes.

      PubDate: 2017-03-02T07:28:36Z
  • Stage-to-stage calculations of distillation columns by fixed-point
           iteration and application of the Banach fixed-point theorem
    • Abstract: Publication date: 8 June 2017
      Source:Chemical Engineering Science, Volume 164
      Author(s): Anna Hoffmann, Michael Bortz, Richard Welke, Jakob Burger, Karl-Heinz Küfer, Hans Hasse
      This work presents a novel approach for stage-to-stage calculations of distillation columns based on the MESH equations. No simplifying assumptions such as constant molar overflow are used. The transition from one stage to the next is formulated as a fixed-point problem, which can be solved by fixed-point iteration. Applying the Banach fixed-point theorem, bounds on the minimum energy requirement are derived. Within these bounds a solution to the fixed-point problem is proven to exist and convergence of the fixed-point iteration is guaranteed. Additionally, energy bounds are derived below which it can be guaranteed that no fixed-point exists. The stage-to-stage calculations are combined with an outer optimization loop in order to conduct process simulation and optimization. The approach is illustrated by examples.

      PubDate: 2017-03-02T07:28:36Z
  • Molecular characterization of petroleum fractions using state space
           representation and its application for predicting naphtha pyrolysis
           product distributions
    • Abstract: Publication date: 8 June 2017
      Source:Chemical Engineering Science, Volume 164
      Author(s): Hua Mei, Hui Cheng, Zhenlei Wang, Jinlong Li
      Molecular model of petroleum fractions plays an important role in the designing, simulation and optimization for petrochemical processes such as pyrolysis process, catalytic reforming and fluid catalytic cracking (FCC). However, it is very difficult to exactly characterize the composition distributions due to its internal complexity and containing numerous redundant information and measuring errors although many efforts have been made so far. As an improvement of the work in Mei et al. (2016), a molecular-based representation method within a multi-dimensional state space is developed in this paper. In this method, each pure component in the petroleum mixtures is defined as a state variable and any petroleum fractions can be geometrically represented as a point in a multi-dimensional linear state space, in which a conception of basis fractions is further introduced by defining a group of linear independent vectors so that any petroleum fractions within the specified range (e.g. naphtha) can be obtained through a linear combination by such basis fractions. The redundant information and measuring errors in the pre-determined petroleum fraction samples are eliminated through the procedure of calculating the basis fractions with non-negative matrix factorization (NMF) algorithm, meanwhile the scale of the feedstock database is highly decreased. As an application example of the basis fractions, a quick prediction approach on naphtha pyrolysis product distributions is developed by linearly combining the pyrolysis products of the basis fractions. In contrast to mechanistic models, this proposed method is more suitable for real-time control and optimization purpose with little loss of accuracy.

      PubDate: 2017-02-16T09:22:48Z
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